Cloud Code supports attaching a debugger
to a Kubernetes pod. All you need to have is a debuggable container and an attach configuration of type cloudcode.kubernetes
.
Setting up a container
You will have to ensure that the container you'd like to debug is debug-ready. Below are the language specific instructions to set up containers to do so.
Node.js
- Start the Node.js application with
--inspect=<debugPort>
wheredebugPort
comes from the attach configuration. For example:CMD ["node", "--inspect=9229", "index.js"]
Python
- Ensure you have the
ptvsd
module installed on your machine and in your container. - Start the Python application through
ptvsd
. Match the port specified to thedebugPort
field in the attach configuration. For example:CMD ["python", "-m", "ptvsd", "--port", "
", "app.py"]
Go
- Ensure you have the
dlv
package installed on your machine and your Go container. Start your Go application through
dlv debug
.The port specified in the starting command should be the same as the
debugPort
attribute value in the attach configuration. For example:CMD ["dlv", "debug", "--headless", "--listen=:<debugPort>", "--log"]
Troubleshooting Tip: When debugging a Go application, the application will stop and wait for a debugger to attach. Attach a debugger for the service to start.
Java
- Ensure that JVM is installed on your machine.
Start the Java application with
-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=<debugPort>,quiet=y
wheredebugPort
comes from the attach configuration.For example, to start the Java application in debug mode and listen on port
debugPort
for connection:ENTRYPOINT ["java","-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=<debugPort>,quiet=y", "-jar", "my-app-1.0.jar"]
.NET Core
Ensure you have the
vsdbg
, the .NET Core command line debugger from Microsoft, installed on your Kubernetes container.For example:
RUN apt-get update
&& apt-get install -y --no-install-recommends unzip
&& apt-get install -y procps
&& rm -rf /var/lib/apt/lists/*
&& curl -sSL https://aka.ms/getvsdbgsh | bash /dev/stdin -v latest -l /vsdbg
Setting up an attach configuration
To attach to a debuggable container, you need to have an attach configuration of type cloudcode.kubernetes
.
Projects that don't have .vscode/launch.json file
If your project doesn't have a launch.json file in its .vscode
folder, you can add one using the Debug panel.
Navigate to the Debug panel (using the Debug view icon
from the Activity bar) and select
Add Configuration
from the dropdown menu.Select
Cloud Code: Kubernetes
as the environment.Select
Attach to Kubernetes Pod
option.Select the corresponding programming language.
This will create and open a
launch.json
file for your project as well as create an attach configuration for you. You can now update configuration attributes in this file to match those of your project. For more information on configuration attributes, refer to this table.
Projects that have .vscode/launch.json file
To add a new attach configuration to an existing .vscode/launch.json:
- Open the launch.json file.
- Press the
Add Configuration
button that invokes the snippet Intellisense. - Select one of the
Cloud Code: Attach to Kubernetes Pod
snippets for the desired language. This will add an attach configuration. You can now update attributes in this configuration to match those of your project. For more information on configuration attributes, refer to this table.
Configuration attributes
Attribute | Description |
---|---|
debugPort | Debug port used on the container. |
podSelector | Set of key-value pairs used to select the debug pod
(for more information, refer to guide on selectors). A typical podSelector is normally:
|
localRoot | Path to the local directory containing the program being debugged. Defaults to ${workspaceFolder}. |
remoteRoot | Absolute path to the remote directory containing the program being debugged (on the Kubernetes container). |
Attaching a debugger to a Kubernetes pod
Once you have set up the configuration and the container:
- Open Debug view
.
- Select and launch the configuration with
F5
.localhost:${debugPort}
will be port-forwarded todebugPort
on the container while debugging.
- The debugging session is now successfully set up!
- You can now perform all the tasks you normally do when debugging local code, like setting breakpoints and stepping through code.
To inspect variables and stack info, use the Debug Sidebar. To interact with the debugging session, use the Debug Console in the bottom pane debugger.
To end the debugging session, click the stop icon on the Debug Toolbar.
Attaching to a Kubernetes pod vs Debugging a Kubernetes application
Attaching to a Kubernetes pod | Debugging a Kubernetes application |
---|---|
Debugs a single Kubernetes pod | Debugs all the debuggable containers in the application |
You'll have to ensure that the application is running in the Kubernetes pod before debugging. | Runs the application on the Kubernetes cluster and attaches the debugger. |
Uses configuration (.vscode/launch.json) of type 'cloudcode.kubernetes' and request 'attach'. | Uses configuration (.vscode/launch.json) of type 'cloudcode.kubernetes' and request 'launch'. launch verses attach configurations. |
Sample Config:
{ "name": "Attach to Kubernetes Pod (NodeJS)", "type": "cloudcode.kubernetes", "request": "attach", "language": "Node", "debugPort": 9229, "podSelector": { "app": "hello-world" }, "localRoot": "${workspaceFolder}", "remoteRoot": "/app" } |
Sample Config:
{ "name": "Run/Debug on Kubernetes", "type": "cloudcode.kubernetes", "request": "launch", "skaffoldConfig": "${workspaceFolder}/skaffold.yaml", "watch": true, "cleanUp": true, "portForward": true } |
This configuration cannot be used to run the application | This configuration can be used for both running or debugging the application. |
This configuration is language specific | This configuration is language agnostic |
No dedicated command | 'Debug on Kubernetes' command |